I chose OCaml because of the relatively mature OCaml-LLVM bindings. A self-hosting compiler is a lot of work: it'll require Rhine-LLVM bindings first.
(Not being snarky, languages and text editors are both interesting projects and worth experimenting with, and combining the two is especially interesting to me.)
emacs, which is utterly unapproachable for newcomers, and will always be uncomfortable to use for people that grew up with "modern" desktop GUIs, because it and most of its userbase predate established interface standards and they like it that way.
DrRacket, which is a step in the right direction but is Racket-specific, bloated, slow, and somewhat buggy.
LispWorks, which is proprietary and prohibitively expensive unless you sign up for and are allowed to use the crippleware version.
Given those choices, it's not surprising that most people just give up on Lisp and use languages that you could comfortably program in Notepad if you had to.
1. Set indent-tabs-mode in all modes which use that variable. So, if I install a hs-mode, the indent-tabs-mode in my .emacs should be the one that it picks up.
2. Add multiple independent hooks to c-mode-hook from different modes.
3. Change the global keymap in different modes, as and when they are loaded.
Isn't mutable variables the most obvious way to solve these problems?
Yes, but the mutation can be entirely limited to the reference. The data structures do not have to be mutable. It's a trade-off, of course, because you can't pass somebody just part of a data structure (like a sub-map) and have them mutate it there, but I think Clojure has shown that in practice this isn't really much of a loss.